Various types of motor vehicles such as cars, trucks, boats, aircraft, and the like, have doors for entrance into, and egress from, the vehicle. Certain such doors have flexible rubber seals which extend around e.g. the outer perimeter of the door to form a seal between the door and the vehicle body when the door is closed. Such seals can be used on doors whose main purpose is personnel entrance or egress; or can be used on other doors such as for sealing a vehicle compartment such as a trunk of a car, or service compartment of a boat or aircraft.
In the alternative, the seal can be mounted to the vehicle body about the door opening so as to interface with the door when the door is closed. The balance of the description herein assumes the seal strip is mounted on the door. However, the description applies equally to having the seal strip mounted about the door opening.
This invention relates to machines which form holes in the strip of rubber door seal material which goes around the doors or door openings of such motor vehicles, and which machines place attachment pins in the holes so formed. Such pins can be inserted into the rubber strip by inserting one leg of the pin into the hole, and forcing the pin sideways along the length of the rubber strip while tilting the pin relative to the rubber strip in a rocking motion so as to stretch the material adjacent the hole and thereby elongate the hole while simultaneously force the second opposing leg of the pin into the so-stretched hole. The pin can be removed from the rubber strip using a generally reverse sequence of steps. The insertion process can, of course, be different where the pin structure is different.
It is known to use automated machines to process extruded rubber strips which are to be used for door seals for the automotive industry. These machines automatically drill holes in the rubber strips at specified distances from each other and insert plastic pins into the holes. The plastic pins are used for mounting the door seal to the vehicle door, at holes disposed about the door. When the correct number of holes and pins are in the rubber strip to constitute the length of a finished seal product, the rubber strip is cut to length, as needed, and the process is repeated to produce another seal product. Conventional such machines produce parts, e.g. finished seal product, in the following manner.
A generally continuous strip of the extruded rubber strip is incrementally fed into the machine using various drive mechanisms until the position, on the rubber strip, for a hole and corresponding pin is located at the drill/pin insertion station. A hole is then drilled into the rubber strip and a pin is inserted.
The rubber strip is again incrementally fed until the position for the next hole and pin is located at the drill/pin insertion station whereupon the next hole is drilled and a pin is inserted into that next hole. The rubber is incrementally fed, and holes drilled and pins inserted, until the programmed number of pins are in the rubber extrusion, whereupon the rubber extrusion is incrementally fed, optionally forming more holes and inserting more pins, until the correct overall length of the part is achieved ata cutoff device. The cutoff device is then actuated to cut the rubber extrusion, separating the completed part from the generally continuous strip of rubber. Throughout the drilling and pinning process, the drilling head is in a fixed location. The pinning head can move relative to the direction of advance of the rubber strip, by any distance required to retrieve a pin from a pin track, and to place the pin in the hole just drilled.
Completed parts are inspected by the machine operator for pin-to-pin dimension and pin-to-end cut dimension. Typical tolerance which can be held for pin-to-pin distance is 1.5 to 3 millimeters, and which can be held for pin-to-end cut distance is 3 to 5 millimeters. Over a period of time, the dimensions measured in the finished parts commonly drift away from the target dimensions. Such drifting of dimensions is usually caused by minor changes in the durometer of the rubber extrusion from batch to batch in combination with the dimensional instability, deformability of typical rubber, elastomer-type materials. Also, rubber is sometimes extruded from a number of extruders, or can be extruded from a plurality of dies, which can also cause differences in durometer and/or extrusion profiles, both of which can affect the actual magnitudes of distances of interest in the finished parts. The changes in durometer, or physical profile of the extrusion can cause the rubber to exhibit, for example, more or less elasticity, accompanied by a greater or lesser stress/strain ratio in the rubber extrusions, which manifests itself by the dimensions drifting away from the target dimensions.
As the dimensions drift, and are detected by the operator as a result of inspecting the finished product parts, the operator calculates a compensation factor which he or she then enters into the machine control. The machine control adds or subtracts the compensation factor, as appropriate, to the incremental feed distance instructions sent to the feeding device at each increment of feeding the rubber strip to the work station, in an attempt to bring the length dimensions in subsequent work pieces back closer to the target dimensions.
The operator continuously performs finished parts inspections and regularly enters compensating adjustments corresponding to the results of such inspections.
End users of the rubber extrusions with pins continually seek better quality seals, parts. The end user has an urgent need for tighter pin-to-pin tolerances and tighter pin-to-end cut tolerances, as well as in-process inspection to ensure proper pin insertion. Current tolerance targets are 1 mm or better pin-to-pin tolerance and 2 mm or better pin-to-end cut tolerance. Achieving tight tolerances, using conventional technology, has been limited by the dimensional instability of the rubber. For example, the rubber is readily stretched, compressed, flexed transversely, and the like, all of which contribute to difficulty in forming a hole precisely at a predetermined location along the length of the rubber strip.
Additionally, the rubber seal fabricator wants to reduce scrap and does not want the operator to have the capability to manually influence the quality of the finished extrusion door seal product.
The basic problem addressed by the invention is that the holes in the pinned rubber must match up with corresponding receptor holes formed in the e.g. metal door of the vehicle. While the locations of the holes in the door can readily be held to close tolerance because the metal is rigid, it is more difficult to hold close tolerances on formation of holes in the rubber strip, hole-to-hole, or hole-to-end cut, because the rubber strip is more flexible, and is otherwise more deformable. For example, if the rubber strip gets stretched or compressed or flexed as the rubber strip is being fed into the hole forming position, the position of the hole so made, or a subsequent hole, when the rubber strip is relaxed, can be displaced from its desired location by an undesirable distance. If the hole is thus unacceptably displaced from the desired location, the door seal may not fit properly on the door, and may compromise at least part of the desired sealing affect between the door and the doorway opening in the vehicle body.
Conventionally available seal material processing machines, running at commercial speeds, with typical operators, can produce seal products wherein variance between target hole-to-hole distance and actual hole-to-hole distance, averages about 1.5 mm to about 3 mm of the target distances between holes. Average variance from target, of hole-to-cut off end of the part, is about 3 mm to about 5 mm. The objective of the invention is to reduce the average variances from target distances. Any reduction in variance below the conventionally available variances is an improvement, and thus can be within the scope of the invention. Variance of no more than 1 mm, hole-to-hole, is highly desired. Variance of no more than 2 mm, preferably no more than 1 mm, hole-to-cut off end, is highly desired.
In the conventional machines described hereinabove, the drilling head and the pinning head are mounted on separate supports. The drilling head is generally stationary. The pinning head has sufficient mobility to pick up a pin from a pin feed tray, to move under the drilling head when the drilling head is retracted from a drilled hole, and to install the pin into the hole. Both the drilling and the pinning steps are accomplished while the strip of flexible seal material is stationary.
Still referring to conventional machines, the feed drive which advances the rubber strip is set to intermittently feed increments of the raw material rubber strip in specified feed drive distance increments. Namely, a specified length of the rubber strip is fed into the machine, and stopped. The drilling and pinning devices drill a hole and insert a pin. The rubber strip is then fed the next incremental distance between holes to be formed, and stopped, whereupon a second hole is drilled and pinned. When the desired number of holes and pins have been applied to a desired length of the work piece, the rubber strip is cut for length, creating a finished part, and a new drilling and pinning sequence is started, to create a second seal product. In the alternative, additional holes can be drilled, and pins inserted, in a trailing length of the rubber strip while the first length concurrently advances, as part of the work piece still being drilled and pinned, to a downstream cut-off device.
Yet referring to conventional operations, selected ones of the finished parts are inspected by an operator for distances between respective holes in the work piece and for distances from the end pins to the ends of the work piece. The operator then adjusts the setting on the drive apparatus which drives feeding of the rubber strip through the machine, in accord with the findings of one or more such inspections. Meantime, while the operator is taking the measurements and determining desired adjustments, several more finished parts can have been produced at the existing drive distance setting. To the extent there was a drive distance error in the part which was inspected, the several more finished parts may have similar errors, and further, the magnitude of the error may have changed before the operator has made any adjustment.
So the operator's adjustment in conventional operations, while potentially precise with respect to the finished part measured, while potentially helpful in retaining the produced parts within the outer limits of a specified tolerance, lacks some desired element of precision as far as returning the hole-to-hole distance, or the hole-to-end distance, to the desired target magnitude. The operator thus continues to adjust the drive belt drive setting according to hindsight inspection of the finished parts coming off the machine. And only a small fraction of the finished parts can be inspected by hand. The end result is that a skilled worker can manage to hold tolerance of hole-to-hole distances to only about 1.5 mm to about 3 mm of the specified target distances.
Accordingly, it is an object of the invention to provide a door seal processing machine for receiving a generally continuous, or defined length, strip of seal material and fabricating door seal products therefrom, the machine including a track which mounts hole forming and pinning apparatus to a machine frame, a sensor sensing holes in the seal material, and a controller receiving the sensor output and using such output to compute and issue drive commands to a driver driving the hole forming and pinning apparatus along the track to a desired hole forming location.
It is a further object to provide such machine wherein the controller is programmed with instructions instructing movement of the hole forming and pinning apparatus back and forth along the track to form holes, and insert pins in the holes, optionally between a hole forming section of a work station, and a pinning section of the work station.
It is yet another object to provide a such machine including a detector detecting the location of the forming and pinning apparatus along the track, and sending such detect information to the controller which uses such location information in determining subsequent movement instructions for movement of the hole forming and pinning apparatus along the track.
It is still another object to provide a such machine wherein the controller uses the hole position information, as sensed by the sensor for one hole, both to instruct positioning of the hole forming and pinning apparatus for forming and pinning a hole, and to instruct a work piece driver regarding the incremental feed drive movement required to feed the desired length of door seal material to the work station at a given incremental feed event.
It is a still further object to provide, as the sensor, a visual image camera.
Still another object is to provide, as the sensor, a visual image camera, and optionally to further provide, in the camera memory or the controller memory, reference images which are representative of the work piece image profile desired, and to compare a reference image to an image captured by the camera.
Yet another object is to provide a method of processing door seal material including, while maintaining the door seal material in a longitudinally fixed location, moving the hole forming apparatus along the length of the seal material to a location, displaced from a hole being sensed, and forming a subsequent hole.
It is a still further object to provide a method using the sensed position of a first hole as basis for longitudinally positioning the hole forming apparatus and forming the next hole.
A still further object is to provide a machine and method of forming holes at a first location along a path of travel of the seal material and inserting pins at a second location, displaced from the first location, along the path of travel of the seal material, and optionally moving the hole forming and pinning apparatus back and forth between the forming and pinning locations.
Yet another object is to provide a method of forming holes in a strip of flexible door seal material, including sensing a hole, determining a location for forming a subsequent hole based on the location of the sensed hole, and moving movable hole forming apparatus, as necessary, along the length of the flexible strip, all while maintaining the strip of flexible door seal material in longitudinally-fixed locations.
Still another object is to provide a such machine and method of forming holes wherein the rubber strip is temporarily fixedly mounted in a fixture which moves along a fixture track, relative to the hole forming and pinning apparatus, and wherein a movement detector detects distance of movement of the fixture along the fixture track, or a sensor senses position of a sensed element of the fixture or work piece, along the track, and communicates such distances and locations to the controller, whereby the strip does not move relative to the fixture after a pin has been inserted and before the next hole is drilled.
Yet another object is to provide such machine and method wherein a length of the continuous-length flexible work piece material, corresponding to the length of a finished unit of product, is fed onto the work station, and clamped in the fixture, and the drilling and pinning head, preferably with commonly-mounted camera, is moved along the work piece length and caused to form holes, and insert pins into the holes along the full length of the work piece without unclamping the work piece from the fixture.
It is an object to provide such machine and method wherein a first/leading hole in the work piece is located based on the sensed relative position of an already-formed hole in a previously formed work piece.